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84.86 (C-1), 78.36 (C-3), 76.13 (C-2), 75.18 (CH2Ph),
73.51 (CH2Ph), 72.80 (C-4), 72.57 (C-5), 72.18
(CH2Ph), 68.49 (C-6). Anal. Calcd for C35H33F3O6S: C,
65.82; H, 5.21; F, 8.92; S, 5.02. Found: C, 65.48; H,
5.12; F, 8.93; S, 5.22.
H-3III), 5.36 (dd, 1 H, J 2.9, 9.3 Hz, H-3II), 5.31 (t, 1 H,
J 9.3 Hz, H-4II), 5.27 (d, 1 H, J 1.7 Hz, H-1III), 5.23
(dd, 1 H, J 1.2, 17.1 Hz, CHꢀCH2), 5.16 (dd, 1 H, J 1.2,
10.5 Hz, CHꢀCH2), 5.01 (d, 1 H, J 1.7 Hz, H-1II), 4.93
(d, 1 H, J 1.5 Hz, H-1I), 4.80 (d, 1 H, J 10.7 Hz,
ꢁCH2Ph), 4.69–4.34 (m, 11 H, ꢁCH2Ph), 4.18–4.09 (m,
6 H, H-5II, 6II, 6%II, 4III, 5III, CH2CHꢀCH2), 4.02–3.88
(m, 5 H, H-2I, 3I, 2II, 2III, CH2CHꢀCH2), 3.83 (t, 1 H,
J 9.0 Hz, H-4I), 3.77–3.55 (m, 5 H, H-5I, 6I, 6%I, 6III,
6%III), 1.99 (s, 3 H, Ac), 1.97 (s, 3 H, Ac), 1.95 (s, 3 H,
Ac). 13C NMR (CDCl3): 170.78, 169.39, 169.24 (3×
CꢀO), 133.42 (CHꢀCH2), 117.16 (CH2CHꢀCH2),
100.01 (C-1III), 98.79 (C-1II), 97.75 (C-1I), 77.70 (C-3III),
76.16 (C-2I), 75.96 (C-5III), 75.15, 74.97 (2×CH2Ph),
74.85 (C-4I, 2II), 74.34, 73.06 (2×CH2Ph), 72.83 (C-
4III), 72.71, 72.12 (2×CH2Ph), 71.92 (C-2III), 71.71
(C-5I), 70.30 (C-3II), 69.00 (C-6I), 68.78 (C-5II), 68.59
(C-6III), 67.92 (CH2CHꢀCH2), 66.43 (C-4II), 62.14 (C-
6II), 20.90, 20.75, 20.69 (3×Ac). Anal. Calcd for
C71H77F3O20: C, 65.23; H, 5.94; F, 4.36. Found: C,
64.98; H, 5.95; F, 4.29.
3.7. 2,4,6-Tri-O-benzyl-1-thio-3-O-trifluoroacetyl-a-
D-
mannopyranosyl fluoride (10)
To a stirred solution of 12 (730 mg, 1.14 mmol) in
CH2Cl2 (10 mL) was added DAST (227 mL, 1.71 mmol)
and NBS (325 mg, 1.83 mmol) at −40 °C. The mixture
was gradually warmed up to −10 °C and stirred
overnight. After the reaction was quenched with
MeOH, the mixture was diluted with AcOEt and
washed with satd NaHCO3, H2O and brine, succes-
sively. The organic extract was dried over MgSO4,
concentrated in vacuo, and purified by silica gel chro-
matography (10:1 hexane–AcOEt) to afford 10 (331
mg, 53%) and the b-isomer (26 mg, 4%). 1H NMR
(CDCl3): l 7.37–7.26 (m, 13 H, aromatic), 7.13–7.10
(m, 2 H, aromatic), 5.62 (dd, 1 H, J 2.0, 49.8 Hz, H-1),
5.33 (ddd, 1 H, J 1.7, 3.2, 9.6 Hz, H-3), 4.69 (d, 1H, J
12.0 Hz, ꢁCH2Ph), 4.64 (s, 2 H, ꢁCH2Ph), 4.63 (d, 1 H,
J 10.6 Hz, ꢁCH2Ph), 4.52 (d, 1 H, J 12.0 Hz, ꢁCH2Ph),
4.49 (d, 1 H, J 10.6 Hz, ꢁCH2Ph), 4.27 (t, 1 H, J 9.8
Hz, H-4), 4.06 (t, 1 H, J 2.7 Hz, H-2), 3.96 (ddd, 1 H,
J 1.7, 3.9, 9.8 Hz, H-5), 3.81 (dd, 1 H, J 3.9, 11.2 Hz,
H-6), 3.71 (dd, 1 H, J 1.7, 11.2 Hz, H-6%). 13C NMR
3.9. Allyl 2,4,6-tri-O-benzyl-a-
2)-3,4,6-tri-O-acetyl-a- -mannopyranosyl-(12)-
3,4,6-tri-O-benzyl-a- -mannopyranoside (14)
D-mannopyranosyl-(1
D
D
Compound 13 (73 mg, 0.054 mmol) was dissolved in
EtOH (3 mL). Pyridine (49 mL, 0.60 mmol) was added,
and the mixture was stirred at rt for 2.5 h and then
1
1
(CDCl3): 105.41 (d, JC,F 223.5 Hz, C-1), 77.32 (C-3),
concentrated in vacuo to afford 14 (65 mg, quant). H
75.16 (CH2Ph), 73.80 (C-5), 73.62 (CH2Ph), 73.52
(CH2Ph), 73.38 (d, J 35.0 Hz, C-2), 71.73 (C-4), 67.84
(C-6). Anal. Calcd for C29H28F4O6: C, 63.50; H, 5.15;
F, 13.85. Found: C, 63.50; H, 5.13; F, 13.93.
NMR (CDCl3): l 7.36–7.12 (m, 30 H, aromatic), 5.86
(tdd, 1 H, J 5.6, 10.5, 17.1 Hz, CHꢀCH2), 5.35 (dd, 1
H, J 2.9, 9.5 Hz, H-3II), 5.32 (d, 1 H, J 2.0 Hz, H-1III),
5.27 (t, 1 H, J 9.0 Hz, H-4II), 5.23 (dd, 1 H, J 1.2, 17.1
Hz, CHꢀCH2), 5.16 (dd, 1 H, J 1.2, 10.5 Hz, CHꢀCH2),
4.99 (s, 1 H, H-1II), 4.93 (d, 1 H, J 1.5 Hz, H-1I), 4.83
(d, 1 H, J 10.5 Hz, ꢁCH2Ph), 4.80 (d, 1 H, J 10.0 Hz,
ꢁCH2Ph), 4.71 (d, 1 H, J 11.7 Hz, ꢁCH2Ph), 4.62 (d, 1
H, J 12.2 Hz, ꢁCH2Ph), 4.60 (d, 1 H, J 12.2 Hz,
ꢁCH2Ph), 4.57 (d, 1 H, J 11.7 Hz, ꢁCH2Ph), 4.55 (d, 1
H, J 12.2 Hz, ꢁCH2Ph), 4.50 (d, 1 H, J 11.7 Hz,
ꢁCH2Ph), 4.47 (d, 1 H, J 10.0 Hz, ꢁCH2Ph), 4.44 (d, 1
H, J 10.5 Hz, ꢁCH2Ph), 4.38 (d, 1 H, J 12.2 Hz,
ꢁCH2Ph), 4.18–4.03 (m, 6 H, H-5II, 6II, 6%II, 2III, 5III,
CH2CHꢀCH2), 3.97–3.61 (m, 12 H, H-2I, 3I, 4I, 5I, 6I,
6%I, 2II, 3III, 4III, 6III, 6%III, CH2CHꢀCH2), 1.99 (s, 6 H,
Ac), 1.96 (s, 3 H, Ac). 13C NMR (CDCl3): 170.65,
169.90, 169.40 (3×CꢀO), 133.47 (CHꢀCH2), 117.13
(CH2CHꢀCH2), 100.15 (C-1III), 98.66 (C-1II), 97.80 (C-
1I), 79.27 (C-3I), 77.95 (C-4III), 76.44 (C-4I), 76.32 (C-2I,
5III), 75.15 (CH2Ph), 74.84 (C-2II), 74.80, 73.18, 73.04,
72.61, 71.97 (5×CH2Ph), 71.64 (C-2III, 5I), 71.42 (C-
3III), 70.43 (C-3II), 69.32 (C-6III), 69.05 (C-6I), 68.71
(C-5II), 67.93 (CH2CHꢀCH2), 66.60 (C-4II), 62.39 (C-
6II), 20.99, 20.80 (3×Ac). Anal. Calcd for C69H78O19:
C, 68.41; H, 6.49. Found: C, 68.34; H, 6.51.
3.8. Allyl 2,4,6-tri-O-benzyl-3-O-trifluoroacetyl-a-
mannopyranosyl-(12)-3,4,6-tri-O-acetyl-a-
D-
D-
mannopyranosyl-(12)-3,4,6-tri-O-benzyl-a-D-
mannopyranoside (13)
A mixture of activated 4A MS (180 mg), AgOTf (39
mg, 0.15 mmol) and SnCl2 (28 mg, 0.15 mmol) in
CH2Cl2 (0.5 mL) was stirred at −20 °C. A solution of
compound 10 (69 mg, 0.125 mmol) and 8 (65 mg, 0.083
mmol) in CH2Cl2 (3.5 mL) was added dropwise via
cannula. The mixture was allowed to gradually warm
up to rt, and it was stirred for overnight. The resulting
mixture was diluted with AcOEt and stirred with ice-
chips and NaHCO3. After 0.5 h, the mixture was
filtered through Celite, and the filtrate was washed
successively with cold water and brine. The organic
extract was dried over MgSO4, concentrated in vacuo,
and purified by silica gel chromatography (2:1 hexane–
1
AcOEt) to afford 13 (99 mg, 88%). H NMR (CDCl3):
l 7.37–7.07 (m, 30 H, aromatic), 5.86 (tdd, 1 H, J 5.6,
10.5, 17.1 Hz, CHꢀCH2), 5.43 (dd, 1 H, J 3.2, 9.3 Hz,